The oldest lock gates on the non-tidal Thames have been lifted back into place at Teddington.

The 11 tonne timber gates, also the largest and heaviest on the river, have been undergoing a two-month long renovation costing £60,000.

Work on the 23ft (7m) x 15ft (4.5m) tail gates from the barge lock was undertaken at the Environment Agency’s Sunbury Yard.

It is estimated that the gates have been in use for more than 40 years and the work and is expected to extend their life by up to 15 years.

The gates are made from African Ekki hardwood also know as red ironwood. EA engineer Andy Robinson said: “On cost benefit basis it was decided not to replace them with steel gates. The gates were in remarkable condition considering their age and needed repairing rather than replacing. “

EA Waterways Team Leader Jed Ramsay said: “The frames of the gates were intact so the main work involved replacing the planking.” He said the lock system at Teddington had enabled the agency to carry out the work without stopping river traffic.

The three locks at Teddington, which include a small, little used skiff lock, make it the largest system on the non-tidal. The barge lock itself was used by the royal barge Gloriana as it carried the Olympic torch downstream and earlier saw scores of boats sailing downstream for the Jubilee Pageant.